In recent years, domestic parts makers are exposed to intense cost competition as parts markets of automobiles, trains, airplanes, machine tools, and the like have been globalized and low-priced parts have been introduced into the markets. For these reasons, each parts manufacturer has taken various cost saving measures in the materials and manufacturing process in order to maintain the competitive power.
As one example of cost saving measures in the manufacturing process, the temperature for the cleaning step has been lowered to normal temperature. By performing parts cleaning which has been performed at a relatively high temperature at normal temperature, the cleaning bath is not required to be heated and the energy cost saving is thus expected, but there is a problem that the performance to be originally required to the cleaning step such as detergency and defoaming property deteriorates.
When the amount of cleaning agent is increased in order to compensate for the detergency, not only the cost saving itself is not achieved as the cost of chemicals increases but also a number of troubles in the process occur so that bubbles generated in the cleaning bath by an increase in the amount of chemicals used overflow from the bathtub.
It has been hitherto investigated to improve the cleaning performance and foam inhibiting property of cleaning agent. For example, the following Patent Literature 1 below discloses a metal cleaning agent composition containing two specific kinds of nonionic surfactant. In addition, the following Patent Literature 2 below discloses a metal cleaning agent containing a specific ionic surfactant, a specific amine compound, an aminocarboxylic acid-based chelating agent, and a carboxylic acid in combination.